<template>
  <div class="spec-preview">
    <img :src="skuInfo.skuDefaultImg" :alt="skuInfo.skuDesc" />
    <div class="event" @mousemove="move"></div>
    <div class="big">
      <img
        :src="skuInfo.skuDefaultImg"
        :alt="skuInfo.skuDesc"
        :style="{ left: -2 * left + 'px', top: -2 * top + 'px' }"
      />
    </div>
    <div
      class="mask"
      ref="mask"
      :style="{ left: left + 'px', top: top + 'px' }"
    ></div>
  </div>
</template>

<script>
import { mapGetters } from 'vuex'
import _ from "lodash"
export default {
  name: 'Zoom',
  data() {
    return {
      left: 0,
      top: 0,
    }
  },
  computed: {
    ...mapGetters('detail', ['skuInfo']),
  },
  methods: {
    move:_.throttle(function(e){
      let x = e.offsetX - this.$refs.mask.clientWidth / 2
      if (x < 0) x = 0
      const maxX = e.target.clientWidth - this.$refs.mask.clientWidth
      if (x > maxX) x = maxX
      let y = e.offsetY - this.$refs.mask.clientHeight / 2
      if (y < 0) y = 0
      const maxY = e.target.clientHeight - this.$refs.mask.clientHeight
      if (y > maxY) y = maxY
      this.left = x
      this.top = y
    },1000/60)
  },
}
</script>

<style lang="less">
.spec-preview {
  position: relative;
  width: 400px;
  height: 400px;
  border: 1px solid #ccc;

  img {
    width: 100%;
    height: 100%;
  }

  .event {
    width: 100%;
    height: 100%;
    position: absolute;
    top: 0;
    left: 0;
    z-index: 998;
  }

  .mask {
    width: 50%;
    height: 50%;
    background-color: rgba(0, 255, 0, 0.3);
    position: absolute;
    left: 0;
    top: 0;
    display: none;
  }

  .big {
    width: 100%;
    height: 100%;
    position: absolute;
    top: -1px;
    left: 100%;
    border: 1px solid #aaa;
    overflow: hidden;
    z-index: 998;
    display: none;
    background: white;

    img {
      width: 200%;
      max-width: 200%;
      height: 200%;
      position: absolute;
      left: 0;
      top: 0;
    }
  }

  .event:hover ~ .mask,
  .event:hover ~ .big {
    display: block;
  }
}
</style>
